A conventional fluorescent lamp has the following disadvantages:
1. When starting the conventional fluorescent lamp, a high current must be applied to heat the lamp filaments to easily blacken the tube to ultimately fail.
2. The electromagnetic waves caused from the high frequency induction coil for starting the fluorescent lamp is hazardous to human health.
3. The lamp is not adjustable for varying the illumination or light intensity, being unsatisfactory for the lamp user.
The present inventor has found the drawbacks of conventional fluorescent lamp and invented the present device for obtaining a two-electrode lamp having high efficiency and being adjustable for lamp.
The object of the present invention is to provide a lighting device for two-electrode lamp including a plurality of voltage-multiplier rectifying circuits parallelly connected to two electrodes of the fluorescent lamp with stepping voltages, for instance, high, medium and low voltage levels, whereby upon selection of the desired voltage level, the light of the fluorescent lamp can be adjusted optimumly.
Another object of the present invention is to provide a protective device to limit current or to prevent from over current as fed back by the reverse voltage from the lamp and led to the lighting circuit of the two-electrode lamp.